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Quesada C.A.,University of Leeds | Quesada C.A.,National Institute of Amazonian Research | Lloyd J.,University of Leeds | Schwarz M.,Max Planck Institute fuer Biogeochemie | And 27 more authors.
Biogeosciences | Year: 2010

Soil samples were collected in six South American countries in a total of 71 different 1 ha forest plots across the Amazon Basin as part of the RAINFOR project. They were analysed for total and exchangeable cations, C, N, pH with various P fractions also determined. Physical properties were also examined and an index of soil physical quality proposed. A diverse range of soils was found. For the western areas near the Andean cordillera and the southern and northern fringes, soils tend to be distributed among the lower pedogenetic levels, while the central and eastern areas of Amazonia have more intensely weathered soils. This gives rise to a large variation of soil chemical and physical properties across the Basin, with soil properties varying predictably along a gradient of pedogenic development. Nutrient pools generally increased slightly in concentration from the youngest to the intermediate aged soils after which a gradual decline was observed with the lowest values found in the most weathered soils. Soil physical properties were strongly correlated with soil fertility, with favourable physical properties occurring in highly weathered and nutrient depleted soils and with the least weathered, more fertile soils having higher incidence of limiting physical properties. Soil phosphorus concentrations varied markedly in accordance with weathering extent and appear to exert an important influence on the nitrogen cycle of Amazon forest soils. © 2010 Author(s).

Arbelaez-Cortes E.,Institute Investigacion Of Recursos Biologicos | Torres M.F.,Institute Investigacion Of Recursos Biologicos | Torres M.F.,University of Edinburgh | Lopez-Alvarez D.,University of Zaragoza | And 3 more authors.
Acta Biologica Colombiana | Year: 2015

Collections of frozen tissue samples stand as keystone sources of molecular information to construct biodiversity knowledge, and are particularly challenged if they focus on megadiverse countries. In 1998 the Humboldt Institute (Instituto de Investigación de Recursos Biológicos Alexander von Humboldt) began a tissue collection of Colombian biodiversity (IAvH-CT) and the aim of this work is to present a diagnostic and an historical perspective for that collection, constructed by compiling information and experiences on its management as well as by organizing and curating the information of each catalogued sample. After 16 years, the IAvH-CT harbors 16,469 samples, which represent around 2530 species from 1289 genera, and 323 families of the Colombian biodiversity. Samples are biased toward plants (44%) and birds (40%), but also include other animal taxa. Geographically, IAvH-CT includes samples from all Colombian departments, but there is broad variation in their coverage. When compared with other international collections, IAvH-CT fulflls several standards of sample storage and data management, but its major weakness is that several tissues seem to lack a vouchered specimen. Tissues housed at IAvH-CT have been included in at least 48 studies published in several scientifc journals. IAvH-CT is implementing strategies to improve curatorial standards, fll-in taxonomic gaps, and to explore the potential of its samples to understand the outstanding Colombian biota in a cooperative research framework among institutions. © 2015, Universidad Nacional de Colombia. All rights reserved.

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